Method for manufacturing biochip having improved fluorescent signal sensing properties and biochip manufactured by the same

ABSTRACT

A method for manufacturing a biochip having improved fluorescent signal sensing properties, and a biochip manufactured by the manufacturing method. A filter layer is provided between a bio-layer and a light sensor layer so as to remove noise generated by stray light during a bio-reaction process. Thereby, the sensitivity of the light sensor layer can be enhanced.

BACKGROUND

1. Technical Field

Exemplary embodiments of the present disclosure relates to a method formanufacturing biochips and a biochip manufactured by the method, andmore particularly, to a method for manufacturing a biochip havingimproved fluorescent signal sensing properties which can provide alocation-based multi-sensing function and be applied to a real-timequantitative PCR (polymer chain reaction), and a biochip manufactured bythe manufacturing method.

2. Related Art

Generally, a biochip is formed by regularly arranging reference samplesincluding biological material such as DNA or proteins on a substratemade of material such as glass, metal such as gold, or nylon.

The biochip basically uses biochemical reactions between the referencesample fixed to the substrate and a target sample. Representativeexamples of the biochemical reaction between the reference sample andthe target sample include the complementary binding of DNA bases, anantigen-antibody immune reaction and so forth.

Optical-based quantitative and qualitative diagnosis using the biochipis generally performed by detecting the degree of a biochemical reactionbetween the reference sample and the target sample through a process inwhich a result product of the biochemical reaction is converted intodetectable light. Optical conversion media which are generally used arebased on color formation, chemiluminescence, fluorescence, etc.resulting from chemical combination.

FIG. 1 is a view illustrating a conventional fluorescent reactiondetection system.

Referring to FIG. 1, the conventional fluorescent reaction detectionsystem includes a light source 10, a band-pass filter 20, a biochemicalreaction device 30, a fluorescent band-pass filter 40 and a lightsensing device 50 which are separated from each other.

When the distance between the biochemical reaction device 30 in which abiochemical reaction takes place and the light sensing device 50 isdenoted by R and a radius of an opening of a light sensor in the lightsensing device 50 is denoted by r, the quantity of fluorescent lightthat is incident on the light sensor, compared to the total quantity (I)of fluorescent light generated as the result of the biochemicalreaction, is reduced to I(πr2)/(4πR2) with loss of a lot of lightsignals.

Therefore, if the ratio of r/R is reduced, the quantity of light that isincident on the light sensor is reduced, whereby the sensitivity isreduced. As the ratio of r/R approaches 1, the sensitivity becomesincreased. To maximize the sensitivity, there is the need for embodyingthe system such that the light sensor and the location of thebio-reaction region are as close to each other as possible.

FIG. 2 is a sectional view of a biochip provided with a light sensor soas to solve the above-mentioned conventional problem.

Referring to FIG. 2, the conventional biochip 100 provided with a lightsensor includes a bio-layer 110 and a light sensor layer 120.

The bio-layer 110 includes a reaction region 111 in which a biochemicalreaction between a reference sample 111 a and a target sample 111 btakes place. Furthermore, to make it possible to determine a result ofthe biochemical reaction, the bio-layer 110 is embodied in such a waythat luminescent or fluorescent material remains in the reaction region111 depending on the degree of reaction.

In the case where luminescent material remains, there is no need for aseparate light source because external environment has only to be formedsuch that the luminescent material itself emits light. However, in thecase where fluorescent material remains, a separate light source isrequired to excite the fluorescent material.

For this, the conventional technique uses the following method: aseparate external light source and a fluorescent band-pass filter areprovided on an upper end of the optical sensor, or a light emittingdevice 112 having a reflective plate 113 in a lower portion thereof isinstalled in the bio-layer 110, so that light emitted from the lightemitting device is used to excite the fluorescent material in thebio-layer.

However, in the conventional biochip, while fluorescent signals arecreated as a result of a biochemical reaction by means of light emittedfrom the external light source and the internal light emitting device,noise signals of an excitation light that reach thousands to tens ofthousands of times more than the fluorescent signals are also generated.Such noise signals enter the light sensor layer, thus making itdifficult to correctly detect fluorescent signals resulting from thebiochemical reaction.

SUMMARY

Various embodiments are directed to a method for manufacturing a biochiphaving improved fluorescent signal sensing properties and a biochipmanufactured by the method, in which: a light emitting device providedwith a metal wiring layer under a lower portion thereof is formed in abiochip to excite fluorescent material; a fluorescent-excitation-lightband-reject-filter layer for blocking excitation light required forfluorescence is separately formed in a boundary between a bio-layer anda light sensor layer; and a color filter layer is formed on an uppersurface of the light sensor layer to block excitation light and allowfluorescent signals to pass therethrough depending on a band ofwavelength of the fluorescent material, whereby excitation light noisegenerated from the bio-layer can be blocked as much as possible frombeing incident on the light sensor layer, thus making it possible todetect more minute fluorescent signals.

In an embodiment, a method for manufacturing a biochip having improvedfluorescent signal sensing properties includes: forming a light sensorlayer including a plurality of light sensing units, on a semiconductorsubstrate; planarizing a surface of the light sensor layer; forming afilter layer over the planarized light sensor layer; and forming abio-layer over the filter layer, the bio-layer having a plurality ofreaction regions in each of which a biochemical reaction between areference sample and a target sample takes place, with light emittingdevices embedded in the bio-layer, wherein light emitted from each ofthe light emitting devices is blocked from being incident on thecorresponding light sensing unit.

In another embodiment, a biochip having improved fluorescent signalsensing properties includes: a bio-layer embedded with light emittingdevices each of which has a metal wiring layer lying thereunder, andformed with a plurality of reaction regions in each of which abiochemical reaction between a reference sample and a target sampletakes place; a filter layer formed under the bio-layer; and a lightsensor layer which is formed under the filter layer, and in which aplurality of light sensing units are formed, wherein the filter layer isformed by planarizing an upper portion of the light sensor layer andstacking nanoscale thin films through an atomic layer deposition (ALD)process, and light emitted from each of the light emitting devices isblocked from being incident on the corresponding light sensing unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a typical fluorescent reaction detectionsystem;

FIG. 2 is a sectional view of a biochip provided with a conventionallight sensor;

FIG. 3 is a flowchart of a method of manufacturing a biochip havingimproved fluorescent signal sensing properties according to the presentdisclosure.

FIGS. 4A to 4D are sectional views corresponding to the flowchart of thebiochip manufacturing method according to the present disclosure;

FIG. 5 is a flowchart showing a detailed process of a filter layerforming step of the biochip manufacturing method according to thepresent disclosure;

FIG. 6 shows sectional views corresponding to the flowchart of thedetailed process of the filter layer forming step of the biochipmanufacturing method according to the present disclosure;

FIG. 7 is a flowchart showing a detailed process of an embodiment of abio-layer forming step of the biochip manufacturing method according tothe present disclosure;

FIG. 8 is a flowchart showing a detailed process of another embodimentof the bio-layer forming step of the biochip manufacturing methodaccording to the present disclosure;

FIG. 9 is a flowchart showing a detailed process of yet anotherembodiment of the bio-layer forming step of the biochip manufacturingmethod according to the present disclosure;

FIG. 10 is a view illustrating the structure of a biochip havingimproved fluorescent signal sensing properties according to anembodiment of the present disclosure;

FIG. 11 is a view illustrating the structure of a biochip havingimproved fluorescent signal sensing properties according to anotherembodiment of the present disclosure;

FIG. 12 is a view illustrating the structure of a biochip havingimproved fluorescent signal sensing properties according to yet anotherembodiment of the present disclosure;

FIG. 13 is a view relationship in thickness and width of a lightemitting device and a metal wiring layer of the biochip according to thepresent disclosure;

FIG. 14 is a view illustrating the configuration of a light sensing unitof the biochip according to the present disclosure;

FIG. 15 is a view illustrating a system using the biochip according tothe present disclosure;

FIG. 16 is a view illustrating a method of conducting a real timequantitative PCR (polymer chain reaction) using the system with thebiochip according to the present disclosure; and

FIGS. 17A and 17B are views illustrating a method of conducting alocation-based multiplexed diagnosis in a DNA microarray manner usingthe biochip according to the present disclosure.

DETAILED DESCRIPTION

Various embodiments will be described below in more detail withreference to the accompanying drawings. The present disclosure may,however, be embodied in different forms and should not be construed aslimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the present disclosure to those skilledin the art. Throughout the disclosure, like reference numerals refer tolike parts throughout the various figures and embodiments of the presentdisclosure.

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 3 is a flowchart of a method for manufacturing a biochip havingimproved sensing properties according to the present disclosure. FIGS.4A to 4D are sectional views corresponding to the flowchart of themanufacturing method according to the present disclosure.

Referring to FIGS. 3 and 4, the biochip manufacturing method accordingto the present disclosure includes a light-sensor-layer forming stepS100, a planarization step S200, a filter-layer forming step S300 and abio-layer forming step S400.

At the light-sensor-layer forming step S100, a plurality of lightsensing units are provided on a semiconductor substrate, thus forming alight sensor layer 430 (refer to FIG. 4A).

It is preferable that a photodiode be used as each of the light sensingunits 431. Furthermore, to ensure reliable operation of a fluorescentsensing system of the present disclosure and increase a sensing range,photodiodes having different sizes are combined in a photodiode array.

Meanwhile, taking a light penetration depth of a light source intoaccount, a depth to which each photodiode is disposed is preferablyadjusted. In this way, a filtering function can be complemented.

That is, at the light-sensor-layer forming step, the depth to which thelight sensing units are embedded can be adjusted taking the lightpenetration depth of the light source into account such that lightemitted from a fluorescent excitation source, in other words, a lightemitting device, can be blocked and most fluorescent light generated bybio-reaction can be absorbed. Thereby, the filtering function can becomplemented.

Typically, a blue-based light source is used as a light emitting devicethat is used for bio-reactions. As such, in the case where the bluelight source is used, each light sensing unit is preferably embedded inthe semiconductor substrate to a depth ranging from 0.2 μm to 0.4 μmfrom the surface of the substrate so that the sensitivity of the lightsensing unit can be enhanced.

At the light-sensor-layer forming step S100, an image signal processor(hereinafter, referred to as an ‘ISP’) which processes signals generatedbefore and after a fluorescent reaction in the light sensor layer andthus is able to obtain a signal resulting from the fluorescent reactionmay be further provided. The detailed operation of the ISP will bedescribed later herein.

At the planarization step S200, an upper portion of the light sensorlayer 430 is planarized (refer to FIG. 4B).

The upper surface of the light sensor layer 430 just after has beenformed is generally uneven and has scratches rather. The reason for thisis because of penetration of impurities or a chemical reaction inducedduring a semiconductor manufacturing process. When, as in the presentdisclosure, one or more layers of nanoscale thin films are formed on adesired surface, if the surface is uneven or scratched, it will not beeasy to correctly deposit the thin films on the uneven or scratchedsurface. Thereby, the geometrical structure of the filter layer maybecome abnormal, whereby filtering characteristics of the filter layermay deteriorate. In addition, even if several tens of filter layers areformed by depositing, e.g., sixteen to forty layers of thin films, thisproblem is not solved but it is accumulated on each filter layer.

Therefore, before the filter layer 420 is formed on the upper surface ofthe light sensor layer 430, an operation of planarizing a target surfaceto be coated with the filter layer 420 is necessarily required.

Although a planarization operation for a typical semiconductormanufacturing process is for reliable formation of an upper structure,the planarization operation in the present disclosure is needed forpreventing the quality of light reaching the light sensor layer fromdeteriorating. Furthermore, the planarization operation makes the filterlayer 420 be more reliably formed on the even surface.

Here, the planarization operation can be performed bychemical-mechanical polishing (CMP).

Although a front side illumination (FSI) image sensor is illustrated inFIG. 4, the present disclosure may be applied to a back sideillumination (BSI) image sensor, of course.

In the case of the FSI image sensor, a metal layer is present below asurface to be coated with the filter layer. Due to this, during theplanarization operation, electrical uniformity may be broken, and it isnot easy to control it. However, in the case of the BSI image sensor,there is no metal layer under a surface to be coated with the filterlayer. Thus, a thin film can be directly deposited on a siliconsubstrate, so that there is no problem caused by a metal layer duringthe planarization operation. Therefore, in terms of performing theplanarization operation, it is more preferable that the BSI image sensorbe used.

Thereafter, at the filter layer forming step S300, the filter layer 420is formed on an upper surface of the planarized light sensor layer 430(refer to FIG. 4C).

Although most light emitted from each light emitting device 412 providedin a bio-layer 410 is blocked by a metal wiring layer 413 and thusprevented from being incident on the light sensor layer 430, some of thelight may being incident on the light sensor layer 430.

Furthermore, some light that is emitted from the light emitting device412 and enters a reaction region 411 in which bio-reaction takes placemay be reflected by the reaction region 411 and then be incident on thelight sensor layer 430.

Such undesirable light that is incident on the light sensor layer 430acts as noise, thus reducing the sensitivity of the image sensor.

To prevent a reduction in sensitivity of the image sensor, it isrequired for forming the filter layer 420 which can block undesirablelight from being incident on the light sensor layer 430. Moreover, it isvery important to adjust the thickness of the filter layer 420 so that adesired filter characteristic curve can be obtained.

The filter layer 420 may be formed through a single deposition processusing a chemical vapor deposition (CVD) or physical vapor deposition(PVD) method. However, in this case, there are problems in that thequality of the formed film is uneven, and the sensitivity of the sensorcannot be ensured to a predetermined level or more.

Therefore, it is more preferable that the filter layer be formed by anatomic layer deposition (ALD) method in such a way that sixteen to fortylayers of nanoscale thin films such as oxide films or nitride films aredeposited one by one.

FIG. 5 is a flowchart showing a detailed process of the filter layerforming step of the biochip manufacturing method according to thepresent disclosure. FIG. 6 shows sectional views corresponding to theflowchart of the detailed process of the filter layer forming step ofthe biochip manufacturing method according to the present disclosure.

Referring to FIGS. 5 and 6, the filter layer forming step S300 includesa color-filter-layer forming step S310, an overcoating and passivationlayer forming step S320, a planarization step S330, afluorescent-excitation-light band-reject-filter layer forming step S340and an insulation-film-layer forming step S350.

At the color-filter-layer forming step S310, a color filter layer 421which allows a fluorescence-band signal generated by bio-reaction topenetrate therethrough while blocking afluorescent-excitation-light-band signal is formed.

Subsequently, an overcoating and passivation layer 422 for protecting acircuit is formed on the color filter layer, at step S320. Thereafter,an upper surface of the overcoating and passivation layer 422 isplanarized to improve the planarity thereof, at step S330.

At the fluorescent-excitation-light band-reject-filter layer formingstep S340, a fluorescent-excitation-light band-reject-filter layer 423which blocks a fluorescent-excitation-light-band signal is formed on theplanarized upper surface of the overcoating and passivation layer 422.

Thereafter, at step S350, nanoscale oxide or nitride thin films arestacked on top of one another on an upper surface of thefluorescent-excitation-light band-reject-filter layer 423, thus formingan insulation film layer 424.

The bio-layer forming step S400 includes forming, on an upper surface ofthe filter layer 420, a bio-layer 410 which includes light emittingdevices 412 and a plurality of reaction regions 411 in each of which abiochemical reaction between a reference sample and a target sampletakes place (refer to FIG. 4D).

Preferably, the reaction regions 411 are defined by forming dam-shapedstructures 414 on the upper surface of the filter layer 420 andconfigured such that reception of a reference sample and a target samplein each reaction region 411 can be facilitated and bio-reaction can beinduced without the samples being contaminated.

At the bio-layer forming step S400, a light emitting device controller(not shown) for controlling the operation of the light emitting devicesand a temperature sensor (not shown) that senses a reaction temperaturein each reaction region 411 and thus controls start and finish of thereaction may be installed in the bio-layer 410.

FIG. 7 is a flowchart showing a detailed process of an embodiment of abio-layer forming step of the biochip manufacturing method according tothe present disclosure.

Referring to FIG. 7, the bio-layer forming step according to anembodiment of the present disclosure includes a metal-wiring-layerforming step S411, a light emitting device forming step S421 and adam-shaped-structure forming step S431.

At the metal-wiring-layer forming step S411, a metal wiring layer forlight blocking effect and wiring is formed on the upper surface of thefilter layer.

Thereafter, at the light emitting device forming step S421, lightemitting devices are provided above the metal wiring layer such that themetal wiring layer can block light emitted from the light emittingdevices from being incident on the light sensing units. Furthermore, inthe present disclosure, the light emitting devices and the metal wiringlayer are disposed vertically above the light sensing unit so thattransfer of light from the light emitting devices to the light sensingunits can be minimized.

At the dam-shaped-structure forming step S431, the dam-shaped structuresare formed on the upper surface of the filter layer such that thereaction regions in each of which a biochemical reaction between areference sample and a target sample takes place are formed between thedam-shaped structures.

FIG. 8 is a flowchart showing a detailed process of another embodimentof the bio-layer forming step of the biochip manufacturing methodaccording to the present disclosure.

Referring to FIG. 8, the bio-layer forming step according to anotherembodiment of the present disclosure includes a metal-wiring-layerforming step S412, a light emitting device forming step S422 and adam-shaped-structure forming step S432.

At the metal-wiring-layer forming step S412, a metal wiring layer forlight blocking effect and wiring is formed on the upper surface of thefilter layer.

Thereafter, at the light emitting device forming step S422, the lightemitting devices are provided above the metal wiring layer such that themetal wiring layer can block light emitted from the light emittingdevices from being incident on the light sensing units. Furthermore, inthe present disclosure, the light emitting device and the metal wiringlayer are disposed vertically above the light sensing units so thattransfer of light from the light emitting devices to the light sensingunits can be minimized.

At the dam-shaped-structure forming step S432, the dam-shaped structuresare formed above the respective light emitting devices such that thereaction regions in each of which a biochemical reaction between areference sample and a target sample takes place are formed between thedam-shaped structures.

Compared to the bio-layer forming step shown in FIG. 7, the bio-layerforming step shown in FIG. 8 differs from it in that the dam-shapedstructures are formed above the respective light emitting devices andthe reaction regions are defined between the dam-shaped structures.

FIG. 9 is a flowchart showing a detailed process of yet anotherembodiment of the bio-layer forming step of the biochip manufacturingmethod according to the present disclosure.

Referring to FIG. 9, the bio-layer forming step according to yet anotherembodiment of the present disclosure includes a dam-shaped-structureforming step S413 and a light emitting device forming step S423.

At the dam-shaped-structure forming step S431, the dam-shaped structuresare formed on the upper surface of the filter layer such that thereaction regions in each of which a biochemical reaction between areference sample and a target sample takes place are formed between thedam-shaped structures. In this embodiment, an inner surface of eachdam-shaped structure is formed in a lens shape so that light emittedfrom the corresponding light emitting device can be prevented from beingincident on the associated light sensing unit when the light isrefracted by and transmitted through the dam-shaped structure having thelens-shaped inner surface.

At the light emitting device forming step S423, the light emittingdevices are formed on outer side surfaces of the dam-shaped structures.

The bio-layer forming step according to each of the embodiments of thepresent disclosure shown in FIGS. 7 through 9 may further include alight-emitting-device coating step of coating the outer surface of eachlight emitting device to prevent the light emitting device from cominginto contact with the reference sample or the target sample in thereaction region and thus prevent a short circuit.

In addition, the bio-layer forming step may further include areflection-prevention-film forming step of forming a reflectionprevention film on the upper surface of the bio-layer to prevent lightemitted from the light emitting device from being reflected by thebio-layer.

FIG. 10 is a view illustrating the configuration of an embodiment of abiochip manufactured by the biochip manufacturing method according tothe present disclosure.

Referring to FIG. 10, a biochip 1000 manufactured by the biochipmanufacturing method according to the present disclosure includes abio-layer 1010, a filter layer 1020 and a light sensor layer 1030.

The bio-layer 1010 includes a metal wiring layer 1013 which is formed onan upper surface of the filter layer 1020 and provided for lightblocking effect and wiring, light emitting devices 1012 which areprovided on upper surface of the metal wiring layer 1013, and dam-shapedstructures 1014 which are provided on the upper surface of the filterlayer 1020 to form a plurality of reaction regions 1011 in each of whicha biochemical reaction between a reference sample and a target sampletakes place.

Each of the light emitting devices 1012 is disposed vertically above thecorresponding light sensing unit 1031 such that light emitted from thelight emitting device 1012 can be prevented from being incident on thelight sensing unit 1031.

Although not shown, the bio-layer 101 may further include a lightemitting device controller and a temperature sensor.

The reaction regions 1011 each of which has a form of depression areformed in the bio-layer 1010. Each of the reaction regions 1011 is aplace where biochemical reaction between a reference sample and a targetsample takes place. The biochemical reaction takes place when the targetsample is added to the corresponding reaction region 1011 in which thereference sample is disposed.

The reference sample is selected from various types of samples that areable to biochemically react with the target sample. The type ofreference sample varies depending on the type of biocheimical reactionintended in the biochip. For example, if the biochemical reaction is anantigen-antibody reaction, the reference sample may be an antigen.

The type of target sample is determined depending on the type ofreference sample. For example, if the reference sample is an antigen,the target sample may be blood or the like.

Preferably, the metal wiring layer 1013 is formed under the lightemitting device 1012 so that light emitted from the light emittingdevice 1012 can be prevented from being incident on the correspondinglight sensor layer 1030.

The light emitting device emits light of a predetermined wavelength (λ1)and is connected to a light emitting device controller (not shown) thatcan control on-off switching or the like. The light emitting device ispreferably a light emitting diode (LED), which emits light uponapplication of current and has excellent light emission efficiency.

The metal wiring layer 1013 may be appropriately changed in shape toprevent light emitted from the light emitting device 1012 from beingincident on the light sensor layer 1030. For example, the metal wiringlayer 1013 may be formed in a form in which it encloses the lightemitting device 1012 and is open only toward fluorescent material thatremains in the reaction region 1011.

The temperature sensor (not shown) senses the temperature in thereaction region 1011 and thus controls start and finish of reaction.

The filter layer 1020 includes a color filter layer 1021 which is formedon the upper surface of the planarized light sensor layer, anovercoating and passivation layer 1022 which is formed on the uppersurface of the color filter layer 1021, a fluorescent-excitation-lightband-reject-filter layer 1023 which is formed on the upper surface ofthe overcoating and passivation layer 1022, and an insulation film layer1024 which is formed by stacking nanoscale oxide or nitride thin filmson the upper surface of the fluorescent-excitation-lightband-reject-filter layer 1023.

The filter layer 1020 is disposed between the bio-layer 1010 and thelight sensor layer 1030 and functions to prevent light emitted from thelight emitting device or light reflected in the reaction region afteremitted from the light emitting device from being incident on the lightsensor layer 1030.

The filter layer 1020 of the biochip according to the present disclosureis formed by an atomic layer deposition (ALD) method in such a way thatsixteen to forty layers of nanoscale thin films such as oxide or nitridefilms are deposited one by one.

The light sensor layer 1030 is disposed under the filter layer 1020 andincludes a plurality of light sensing units 1031.

The light sensing units 1031 are provided on the surface of the lightsensor layer 1030 or embedded to a predetermined depth from the surfacethereof and function to sense light and to produce an electric chargecorresponding to the sensed light. A peripheral circuit (not shown) forproducing an electrical signal based on the produced electric charge isconnected to each of the light sensing unit 1031. Representativeexamples of the light sensing units 1031 include charge coupled device(CCD) type image sensors and complementary MOS (CMOS) type imagesensors.

The light sensor layer 1030 may further include an image signalprocessor (1032, hereinafter referred to as an ‘ISP’) which processessignals generated before and after a fluorescent reaction and thus isable to obtain a signal resulting from the fluorescent reaction.

The ISP 1032 functions process signals reflected by light emitted fromthe light emitting device before and after a fluorescent reaction and toremove temporal noise which may be generated in pixels. This will beexplained in more detail below.

First, a reaction region in which a fluorescent reaction takes place isformed in the bio-layer, and the LED is turned on under the control ofthe light emitting device controller before the fluorescent reaction isperformed.

Here, light emitted from the LED is reflected in the reaction region forfluorescent reaction and then reaches the light sensing unit. The lightsensing unit senses a signal reflected in the reaction region andoutputs an electrical signal (S1).

While this operation is performed n times, reflected signals are sensedand electrical signals (S1) to (Sn) corresponding to the reflectedsignals are output. Subsequently, a mean value of the electrical signalsis calculated. In this way, a mean value of electrical signals beforethe reaction is obtained.

This process is conducted in pixels, and a mean value (S_ext) ofelectrical signals in pixels is obtained and then stored as referencedata.

Thereafter, a fluorescent reaction takes place, and a mean value(S_signal) of electrical signals in pixels is obtained again. Data aboutthe mean value (S_signal) is stored.

Here, the obtained mean value (S_signal) is the sum of the mean value(S_ext) of electrical signals obtained before the fluorescent reactionand a mean value (S_fluorescence) of electrical signals resulting fromthe fluorescent reaction.

Therefore, the signal value (S_fluorescence) resulting from thefluorescent reaction can be calculated by subtracting the signal value(S_ext) obtained before the fluorescent reaction from the signal value(S_signal) obtained after the fluorescent reaction.

As such, after signals are obtained through repetitive measurement, amean value is calculated by integrating the signals, whereby temporalnoise of pixels can be removed. As a result, the sensitivity can beenhanced.

Therefore, preferably, the ISP according to the present disclosure musthave a function of integrating signals and be provided with a memory orthe like as a storage means for calculating and storing data aboutintegrated signals.

In detail, the ISP may include: a first memory which senses signalsreflected by the bio-layer before the fluorescent reaction is performed,integrates the signals, calculates a mean value of electrical signals inpixels, and then stores the mean value; a second memory which sensessignals reflected by the bio-layer after the fluorescent reaction isperformed, integrates these signals, calculates a mean value ofelectrical signals in pixels, and then stores the mean value; and acomparison unit which compares the values stored in the first memory andthe second memory and thus obtains a signal value resulting from thefluorescent reaction.

FIG. 11 is a view illustrating the configuration of another embodimentof a biochip manufactured by the biochip manufacturing method accordingto the present disclosure.

Referring to FIG. 11, a biochip 1100 manufactured by the biochipmanufacturing method according to the present disclosure includes abio-layer 1110, a filter layer 1120 and a light sensing layer 1130.

The configurations and functions of the filter layer 1120 and the lightsensor layer 1130 are the same as those of the filter layer 1020 and thelight sensor layer 1030 illustrated in FIG. 10; therefore, detaileddescription thereof is deemed unnecessary.

The bio-layer 1110 includes a metal wiring layer 1113 which is formed onthe upper surface of the filter layer and provided for light blockingeffect and wiring, light emitting devices 1112 which are provided on theupper surface of the metal wiring layer 1113, and dam-shaped structures1014 which are provided on the respective light emitting devices 1112.

A plurality of reaction regions 1111, in each of which a biochemicalreaction between a reference sample and a target sample takes place, areformed between the dam-shaped structures 1114. Each of the lightemitting devices 1112 is disposed vertically above the correspondinglight sensing unit 1131 such that light emitted from the light emittingdevice 1112 can be prevented from being incident on the light sensingunit 1131.

Compared to the bio-layer 1010 of FIG. 10, the bio-layer 1110 shown inFIG. 11 differs from it in that the dam-shaped structures 1114 areformed above the respective light emitting devices 1112 and the reactionregions 1111 are formed between the dam-shaped structures 1114.

FIG. 12 is a view illustrating the configuration of yet anotherembodiment of a biochip manufactured by the biochip manufacturing methodaccording to the present disclosure.

Referring to FIG. 12, a biochip 1200 manufactured by the biochipmanufacturing method according to the present disclosure includes abio-layer 1210, a filter layer 1220 and a light sensing layer 1230.

The configurations and functions of the filter layer 1220 and the lightsensor layer 1230 are the same as those of the filter layer 1020 and thelight sensor layer 1030 illustrated in FIG. 10; therefore, detaileddescription thereof is deemed unnecessary.

The bio-layer 1210 includes the dam-shaped structures 1214 which areprovided on the upper surface of the filter layer 1220 to form aplurality of reaction regions 1211 in each of which a biochemicalreaction between a reference sample and a target sample takes place, andlight emitting devices 1212 which are provided on outer side surfaces ofthe dam-shaped structures 1214.

In this embodiment, an inner surface of each dam-shaped structure 1214has a lens shape so that light emitted from the corresponding lightemitting device 1212 can be prevented from being incident on theassociated light sensing unit after being reflected by the dam-shapedstructure 1214 having the lens-shaped inner surface.

FIG. 13 is a view relationship in thickness and width between the lightemitting device and the metal wiring layer of the biochip havingimproved fluorescent signal sensing properties according to the presentdisclosure.

As shown in FIG. 13, the thicknesses and the lengths of the lightemitting device and the metal wiring layer and the length of the lightsensing unit of the biochip according to the present disclosure aredetermined by the following equations.

tan θ=t _(L)×(W _(M) −W _(L))/2

W _(PS) =t _(M)/tan θ

W _(P)=2W _(PS) +W _(M)

Here, θ denotes an angle between the upper surface of the light sensingunit and a linear connecting an edge of the upper surface of the lightemitting device, the corresponding edge of the upper surface of themetal wiring layer and the corresponding edge of the upper surface ofthe light sensing unit. t_(L) denotes the thickness of the lightemitting device. t_(M) denotes the thickness of the metal wiring layer.W_(L) denotes the length of the light emitting device. W_(M) denotes thelength of the metal wiring layer. W_(P) denotes the length of the lightsensing unit. W_(P) denotes the length of a portion of the upper surfaceof the light sensing unit above which the metal wiring layer is notpresent.

FIG. 14 is a view illustrating the configuration of a light sensing unitof the biochip having improved fluorescent signal sensing propertiesaccording to the present disclosure.

The light sensing units are provided in the light sensor layer.Preferably, a photodiode is used as each light sensing unit.Furthermore, in the biochip having improved fluorescent signal sensingproperties according to the present disclosure, so as to ensure reliableoperation of the system and increase a sensing range, as shown in FIG.14, unit photodiodes having the same size may be arranged or, morepreferably, a light sensing unit which has a repetitive array ofphotodiodes having sizes integer times that of the unit photodiodes maybe used.

FIG. 15 is a view illustrating a system using the biochip havingimproved fluorescent signal sensing properties according to the presentdisclosure.

A molecular diagnosis kit including the biochip according to the presentdisclosure requires a reader system: which makes a pair with the kit andcompensates for individual deviation of each kit; which operates the kitand peripheral environments such that they are suitable for a reactionsystem of biochemical materials used for molecular diagnosis; whichcontrols the temperature, etc. in response to each operation; and whichcollects, analyzes and processes sensing data obtained from the kit andproduces final molecular diagnosis results.

The molecular diagnosis kit including the biochip according to thepresent disclosure is connected to the reader system by a main controlunit (MCU) and functions to obtain stable and available signals througha process of: processing sensing measurement results; removing varioustypes of noises caused during the sensing process to extract puresignals; and integrating the pure signals.

FIG. 16 is a view illustrating a method of conducting a real timequantitative PCR (polymer chain reaction) using the system with thebiochip according to the present disclosure.

The conventional PCR method is a method of performing an electrophoretictest to check amplified DNA after the PCR and determining whether targetDNA is present in a target sample through checking whether the targetDNA has been amplified. However, in this conventional method, it isimpossible to determine the amount of target DNA before the PCR.

The real time quantitative PCR refers to a method in which amplificationin the amount of DNA resulting from the thermal cycle of PCR is measuredin real time through fluorescence. As the cycle proceeds, the amount offluorescence is increased, and in response to this, a graph is formed.However, depending on an initial amount of DNA, a point (Ct value) towhich the graph exponentially increases is varied. After a PCR standardcurve is obtained from a standard sample, a PCR Ct value of an unknownsample is applied to the standard curve and guantified. In the presentdisclosure, the real time quantitative PCR is possible.

Meanwhile, the present disclosure has a location-based multiplexedmolecular diagnosis function.

The term “multiplexed molecular diagnostics” refers to a method in whichmultiple kinds of target DNA are detected when molecular diagnosis(typically, PCR diagnosis) is conducted. For example, there are severalkinds of bacterium inducing tuberculosis. Thus, when a suspectedtuberculosis patient is tested for tuberculosis, there is the need forchecking the kinds of bacterium that induces the tuberculosis of thepatient. In this case, a method of detecting several kinds of target DNAthrough a single PCR process is preferably used. This method is calledmultiplexed molecular diagnostics.

As such, the multiplexed molecular diagnostics is a method in which asingle PCR tube into which PCR reagent and a sample obtained from thepatient are put is only used to detect several kinds of target DNA. Forthis, different colors of fluorescent materials are used, and detectedseveral kinds of target DNA are distinguished from each other bywavelength bands of fluorescence. However, this method can typicallydetect only six or less kinds of DNA.

A DNA microarray method is another method for conducting thequantitative PCR. This method includes applying target DNA andcomplementary DNA (DNA probe) on the surface of a substrate, and thendetermining whether target DNA is present or not by means of checkingwhether target DNA has been coupled to the DNA probe.

Although this method can detect a large number of kinds of target DNA,there are problems in that, after the PCR has been performed, amplifiedDNA must be applied to a microarray, and several steps are required toobtain a result of the PCR, so that it takes a lot of time to obtain theresult.

The location-based multiplexed molecular diagnosis method according tothe present disclosure is a notion similar to that of the DNA microarraymethod. That is, because a user knows the locations of DNA probes inadvance, it can be appreciated that if fluorescence is generated from alocation, a corresponding kind of target DNA is present. However, unlikethe DNA microarray method, the present disclosure is configured suchthat the PCR and a DNA detection operation can be combined with eachother and thus is advantageous in that the PCR and the DNA detectionprocess can be performed in a single place and the time it takes toperform the detection process can be reduced.

FIGS. 17A and 17B are views illustrating a method of conductinglocation-based multiplexed diagnosis in a DNA microarray manner usingthe biochip according to the present disclosure.

FIG. 17A is a view illustrating a method of detecting several kinds oftarget DNA from different locations in a single PCR reaction chamber inthe case where the locations of DNA probes are known. FIG. 17B is a viewillustrating a method of using a plurality of PCR reaction chambers anddetecting several kinds of target DNA from respective differentchambers.

In a method for manufacturing a biochip having improved fluorescentsignal sensing properties and a biochip manufactured by the methodaccording to the present disclosure, a metal wiring layer and a filterlayer for fluorescent excitation light are provided between a bio-layerand a light sensor layer. Thereby, noise caused from fluorescentexcitation light during a bio-reaction process can be minimized. As aresult, minute-fluorescent-signal sensing performance in the lightsensor layer can be enhanced.

Furthermore, a fluorescent sensor having an improvedminute-fluorescent-signal sensing function, and a bio-LOC (lab on achip) including a bio reaction region having a location-basedmultiplexed function are suitable for application of fluorescence-basedreal-time quantitative PCR, whereby time and cost required to performquantitative molecular diagnosis can be reduced. In addition,industrially, the present disclosure makes it possible to embody variousindustrial models in biomedical markets.

While exemplary embodiments of the present disclosure have beendescribed above, it will be understood to those skilled in the art thatthe embodiments described are by way of example only. Accordingly, thedisclosure described herein should not be limited based on the describedembodiments. Furthermore, those skilled in the art will appreciate thatvarious modifications and changes are possible without departing fromthe technical spirit of the present disclosure.

What is claimed is:
 1. A method for manufacturing a biochip havingimproved fluorescent signal sensing properties, the method comprising:forming a light sensor layer including a plurality of light sensingunits, on a semiconductor substrate; planarizing a surface of the lightsensor layer; forming a filter layer over the planarized light sensorlayer; and forming a bio-layer over the filter layer, the bio-layerhaving a plurality of reaction regions in each of which a biochemicalreaction between a reference sample and a target sample takes place,with light emitting devices embedded in the bio-layer, wherein lightemitted from each of the light emitting devices is blocked from beingincident on the corresponding light sensing unit.
 2. The methodaccording to claim 1, wherein the planarizing is performed through achemical-mechanical planarization process.
 3. The method according toclaim 2, wherein the planarizing comprises: planarizing an upper surfaceof a portion of the light sensor layer in which the plurality of lightsensors are disposed.
 4. The method according to claim 2, wherein theplanarizing comprises: turning the semiconductor substrate upside downand planarizing a rear surface of the portion of the light sensor layerin which the plurality of light sensors are disposed.
 5. The methodaccording to claim 1, wherein the forming of the filter layer comprises:forming a color filter layer for removal of fluorescent light over theplanarized light sensor layer; forming an overcoating and passivationlayer over the color filter layer; planarizing an upper surface of theovercoating and passivation layer; forming afluorescent-excitation-light band-reject-filter layer over theplanarized overcoating and passivation layer; and forming an insulationfilm layer by stacking nanoscale oxide or nitride thin films over theplanarized overcoating and passivation layer.
 6. The method according toclaim 5, wherein the forming of the filter layer is performed through anatomic layer deposition (ALD) process.
 7. The method according to claim1, wherein the forming of the bio-layer comprises: forming a metalwiring layer for light blocking and wiring, over the filter layer;forming the light emitting devices vertically over the metal wiringlayer and the light sensing units; and forming dam-shaped structuresover an upper surface of the filter layer such that the plurality ofreaction regions, in each of which the biochemical reaction between thereference sample and the target sample takes place, are formed betweenthe dam-shaped structures, wherein light emitted from each of the lightemitting devices is blocked from being incident on the correspondinglight sensing unit.
 8. The method according to claim 1, wherein theforming of the bio-layer comprises: forming a metal wiring layer overthe filter layer; forming the light emitting devices vertically over themetal wiring layer and the light sensing unit; and forming dam-shapedstructures over the respective light emitting devices such that theplurality of reaction regions, in each of which the biochemical reactionbetween the reference sample and the target sample takes place, areformed between the dam-shaped structures, wherein light emitted fromeach of the light emitting devices is blocked from being incident on thecorresponding light sensing unit.
 9. The method according to claim 1,wherein the forming of the bio-layer comprises: forming dam-shapedstructures over an upper surface of the filter layer such that theplurality of reaction regions, in each of which the biochemical reactionbetween the reference sample and the target sample takes place, areformed between the dam-shaped structures; and forming the light emittingdevices on outer side surfaces of the dam-shaped structures, wherein aninner surface of each of the dam-shaped structures is formed in a lensshape so that light emitted from the corresponding light emitting deviceis prevented from being incident on the associated light sensing unitwhen the light is refracted by and transmitted through the dam-shapedstructure having the lens-shaped inner surface.
 10. The method accordingto claim 7, further comprising: coating an outer surface of each of thelight emitting devices to prevent the light emitting device from cominginto contact with the reference sample or the target sample in thecorresponding reaction region and thus prevent an electrical shortcircuit.
 11. The method according to claim 1, wherein the forming of thebio-layer further comprises: forming a light emitting device controllerfor controlling operation of the light emitting devices, and atemperature sensor for sensing a temperature in each of the reactionregions and controlling start and finish of a bio-reaction.
 12. Themethod according to claim 1, wherein the forming of the light sensorlayer comprises: burying the light sensing units in the semiconductorsubstrate to a depth ranging from 0.2 μm to 0.4 μm from a surface of thesemiconductor substrate.
 13. The method according to claim 1, furthercomprising: forming a reflection prevention film over the bio-layer toprevent light emitted from the light emitting devices from beingreflected by the bio-layer.
 14. A biochip having improved fluorescentsignal sensing properties, comprising: a bio-layer embedded with lightemitting devices each of which has a metal wiring layer lyingthereunder, and formed with a plurality of reaction regions in each ofwhich a biochemical reaction between a reference sample and a targetsample takes place; a filter layer formed under the bio-layer; and alight sensor layer which is formed under the filter layer, and in whicha plurality of light sensing units are formed, wherein the filter layeris formed by planarizing an upper portion of the light sensor layer andstacking nanoscale thin films through an atomic layer deposition (ALD)process, and light emitted from each of the light emitting devices isblocked from being incident on the corresponding light sensing unit. 15.The biochip according to claim 14, further comprising, in the bio-layer:a light emitting device controller for controlling operation of thelight emitting devices; and a temperature sensor for sensing atemperature in each of the reaction regions and controlling start andfinish of a bio-reaction.
 16. The biochip according to claim 14, whereinthe light sensor layer further comprises: an image signal processor foranalyzing and processing a signal output from the bio-layer.
 17. Thebiochip according to claim 16, wherein the image signal processorcomprises: a first memory which senses signals reflected by thebio-layer before a fluorescent reaction is performed, integrates thesignals, calculates a mean value of electrical signals in pixels, andthen stores the mean value; a second memory which senses signalsreflected by the bio-layer after the fluorescent reaction is performed,integrates the signals, calculates a mean value of electrical signals inpixels, and then stores the mean value; and a comparison unit whichcompares the mean values stored in the first memory and the secondmemory and thus obtains a signal value resulting from the fluorescentreaction, wherein the image signal processor removes temporal noise inpixels and thus enhances sensitivity.
 18. The biochip according to claim16, wherein the filter layer comprises: a color filter layer formed overthe planarized light sensor layer; an overcoating and passivation layerformed over the color filter layer; a fluorescent-excitation-lightband-reject-filter layer formed over the overcoating and passivationlayer; and an insulation film layer formed by stacking nanoscale oxideor nitride thin films over the fluorescent-excitation-lightband-reject-filter layer.
 19. The biochip according to claim 14, whereinthe bio-layer comprises: the metal wiring layer formed over the filterlayer and provided for light blocking and wiring; the light emittingdevices provided over the metal wiring layer; and dam-shaped structuresformed on the upper surface of the filter layer to form the plurality ofreaction regions in each of which the biochemical reaction between thereference sample and the target sample takes place, wherein the lightemitting devices are formed vertically over the respective light sensingunits so that light emitted from each of the light emitting devices isblocked from being incident on the corresponding light sensing unit. 20.The biochip according to claim 14, wherein the bio-layer comprises: themetal wiring layer formed over the filter layer and provided for lightblocking and wiring; the light emitting devices formed over the metalwiring layer; and dam-shaped structures formed over the light emittingdevices, wherein the plurality of reaction regions, in each of which thebiochemical reaction between the reference sample and the target sampletakes place, are formed between the dam-shaped structures, and the lightemitting devices are formed vertically over the light sensing units sothat light emitted from each of the light emitting devices is blockedfrom being incident on the corresponding light sensing unit.
 21. Thebiochip according to claim 14, wherein the bio-layer comprises:dam-shaped structures formed on the upper surface of the filter layer toform the plurality of reaction regions in each of which the biochemicalreaction between the reference sample and the target sample takes place;and light emitting devices formed on outer side surfaces of thedam-shaped structures, wherein an inner surface of each of thedam-shaped structures is formed in a lens shape so that light emittedfrom each of the light emitting devices is prevented from beingreflected by the dam-shaped structure and being incident on thecorresponding light sensing unit.
 22. The biochip according to claim 19,further comprising: a separation structure for separating the lightsensor layer, the filter layer and the bio-layer from an outside. 23.The biochip according to claim 19, wherein each of the dam-shapedstructures is made of at least one selected from among silicone (Si),glass, plastic, sapphire, photoresist, diamond, grapheme and metal. 24.The biochip according to claim 22, further comprising: an isolationcover covering the dam-shaped structures or the separation structure andisolating the reaction regions.
 25. The biochip according to claim 19,wherein thicknesses and lengths of each of the light emitting devicesand the metal wiring layer and the length of the associated lightsensing unit are determined by following equations,tan θ=t _(L)×(W _(M) −W _(L))/2W _(PS) =t _(M)/tan θW _(P)=2W _(PS) +W _(M) where, θ denotes an angle between an uppersurface of the light sensing unit and a linear connecting an edge of anupper surface of the light emitting device, a corresponding edge of anupper surface of the metal wiring layer and a corresponding edge of anupper surface of the light sensing unit, t_(L) denotes a thickness ofthe light emitting device, t_(M) denotes a thickness of the metal wiringlayer, W_(L) denotes a length of the light emitting device, W_(M)denotes a length of the metal wiring layer, W_(P) denotes a length ofthe light sensing unit, W_(PS) denotes a length of a portion of theupper surface of the light sensing unit above which the metal wiringlayer is not present.
 26. The biochip according to claim 14, wherein thelight sensing units comprise: unit photodiodes having a same size, or arepetitive array of photodiodes having sizes integer times the size ofthe unit photodiodes.